The miniaturization and the high integration of a semiconductor element are accelerated. For this reason, generation of a minute foreign material and a defect that is caused by removing or chipping of a stacked film of an end portion of a substrate greatly affects a yield of the product. In order to decrease this influence, bevel polishing to polish the end portion of the substrate with a blade is generally performed.
However, if polishing such as the bevel polishing is performed, a metal such as copper or aluminum to form a circuit may be exposed from a polished portion, and the metal may be contaminated. In particular, in a back surface irradiation type complementary metal oxide semiconductor (CMOS) image sensor that attracts attention in recent years, after bonding two substrates of a device substrate having a copper or aluminum wire and a support substrate, a back surface of the device substrate is mechanically and chemically polished. For this reason, the contamination from the end portion of the substrate may spread over the entire substrate.